Interference mitigation by adjustment of interconnect transmission characteristics

ABSTRACT

Interference within a wireless apparatus is mitigated by adjusting one or more transmission characteristics associated with an interconnect of the apparatus. In at least one embodiment, the interconnect is a PCI Express interconnect.

FIELD OF THE INVENTION

The invention relates generally to interference mitigation and, moreparticularly, to interference mitigation within a wireless system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example apparatus havingwireless communication capability;

FIG. 2 is a block diagram illustrating an example arrangement for use inmitigating interference in accordance with an embodiment of the presentinvention;

FIG. 3 is a block diagram illustrating example spectral shapingequipment that may be used to perform spectral shaping for aninterconnect in accordance with an embodiment of the present invention;

FIG. 4 is a block diagram illustrating an example data rate adjustmentunit in accordance with an embodiment of the present invention;

FIG. 5 is a flowchart illustrating an example method for mitigatinginterference in a wireless apparatus in accordance with an embodiment ofthe present invention;

FIG. 6 is a flowchart illustrating an example method for mitigatinginterference in a wireless apparatus in accordance with an embodiment ofthe present invention; and

FIG. 7 is a flowchart illustrating an example method for negotiating anew data rate for a PCI Express or similar type interconnect wheninterference mitigation is desired in accordance with an embodiment ofthe present invention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that show, by way of illustration, specificembodiments in which the invention may be practiced. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention. It is to be understood that the variousembodiments of the invention, although different, are not necessarilymutually exclusive. For example, a particular feature, structure, orcharacteristic described herein in connection with one embodiment may beimplemented within other embodiments without departing from the spiritand scope of the invention. In addition, it is to be understood that thelocation or arrangement of individual elements within each disclosedembodiment may be modified without departing from the spirit and scopeof the invention. The following detailed description is, therefore, notto be taken in a limiting sense, and the scope of the present inventionis defined only by the appended claims, appropriately interpreted, alongwith the full range of equivalents to which the claims are entitled. Inthe drawings, like numerals refer to the same or similar functionalitythroughout the several views.

FIG. 1 is a block diagram illustrating an example apparatus 10 havingwireless communication capability. The apparatus 10 may be, for example,a desktop, laptop, palmtop, or tablet computer, a personal digitalassistant (PDA), a cellular telephone or other form of wirelesscommunicator, a pager, a Bluetooth enabled appliance, and/or any otherform of wireless apparatus. As shown, the apparatus 10 may include oneor more of a host central processing unit (CPU) 12, a host chipset 14, awireless unit 16, a graphics unit 18, a memory 22, and a wired localarea network (LAN) module 24.

The host CPU 12 is the main processor of the apparatus 10 and may beused to, for example, execute software such as operating systemsoftware, application software, and/or others. The host chipset 14 is adevice or devices that operates in support of the host CPU 12 and mayperform one or more predefined functions for the host such as, forexample, data transfer functions, power management functions, and/orothers. The graphics unit 18 is operative for controlling the display ofinformation to a user of the apparatus 10. The memory 22 stores digitalinformation for use by the host CPU 12 and possibly for other componentswithin the apparatus 10. The wired LAN module 24 is operative forproviding an interface to a wired LAN.

The wireless unit 16 includes circuitry for supporting wirelesscommunication with one or more external entities. In at least oneembodiment, the wireless unit 16 is configured to support one or morewireless standards that may include, for example, IEEE 802.11a, b, g;HyperLAN 1, 2; Bluetooth; Ultra Wideband; HomeRF; Wide Band FrequencyHopping; Digital Enhanced Cordless Telephone (DECT); cellular standards(e.g., global system for mobile communication (GSM), personal digitalcellular (PDC), code division multiple access (CDMA) (IS-95), CDMAOne,CDMA 2000, advanced mobile phone system (AMPS)), and/or others. Thewireless unit 16 may be coupled to an antenna 26 or other transducer tofacilitate transmission and/or reception of wireless signals. Any of avariety of different antenna types may be used including a dipole, amonopole, a patch, a helix, and others. As illustrated, in at least onepossible arrangement, the wireless unit 16 may communicate with a remotewireless local area network (WLAN) access point (AP) 28. Manyalternative arrangements are also possible. It should be appreciatedthat the architecture and content of the apparatus 10 of FIG. 1 ismerely an example of one possible wireless apparatus configuration andis not intended to limit the scope of the invention.

With reference to FIG. 1, the apparatus 10 may include one or moreinterconnects 30, 32, 34, 36, 38 to provide communication between thevarious components of the apparatus 10. The interconnects may includepoint-to-point interconnects, bus structures, and/or any other form ofinterconnect. As with the speeds of digital processors, the speeds ofinterconnects within digital systems have been increasing. For example,the nominal speed of the PCI Express interconnect technology is 2.5Gigabits per second (Gb/s). In conceiving the present invention, it wasappreciated that interconnect speeds are rapidly approaching, and somehave already reached, a level where they may present a significantsource of interference to wireless circuitry within, for example, anapparatus (e.g., wireless unit 16 in FIG. 1). In this regard, methodsand structures are provided herein for mitigating such interferencethrough active manipulation of one or more interconnect transmissioncharacteristics.

FIG. 2 is a block diagram illustrating an example arrangement 50 for usein mitigating interference in accordance with an embodiment of thepresent invention. The arrangement 50 may be implemented within, forexample, the apparatus 10 of FIG. 1 or within virtually any otherdigital apparatus having wireless capability. As illustrated, thearrangement 50 may include one or more of: an interference detector 52,a spectral shaping unit 54, and an interconnect 56.

The interference detector 52 is operative for detecting the presence ofinterference that may affect or has affected the performance of wirelesscircuitry (e.g., a wireless transmitter, a wireless receiver, a wirelesstransceiver, etc.) within an apparatus. When interference of asufficient level or effect has been detected, the interference detector52 signals the spectral shaping unit 54 to modify one or more of thetransmission characteristics of the interconnect 56 in a manner that mayreduce the level of interference within the wireless circuitry. Forexample, in at least one implementation, the spectral shaping unit 54changes a data rate associated with the interconnect 56 in response todetection of interference. In another implementation, the spectralshaping unit 54 changes a slew rate associated with the interconnect 56.Other transmission characteristics may alternatively be changed.Multiple different characteristics may also be changed (e.g., data rateand slew rate, etc.). In at least one approach, the goal of themodification made by the spectral shaping unit 54 is to change thespectrum of the interconnect traffic in a manner that reduces the levelof spectral energy that falls within an operational frequency range ofthe wireless circuitry.

The interconnect 56 may be any form of digital interconnect includingpoint-to-point interconnects, bus structures, etc. In the illustratedexample embodiment, the interconnect 56 is a PCI Express typeinterconnect having a separate link for each direction of communicationbetween two components. Other types of interconnect, includinginterconnects having a single unidirectional or bi-directional link, mayalso be used. In at least one embodiment, the arrangement 50 isimplemented for an interconnect that is coupled directly to wirelesscircuitry within an apparatus (e.g., interconnect 30 coupled betweenwireless unit 16 and host chipset 14 in FIG. 1). However, the same orsimilar arrangement may also (or alternatively) be used in associationwith one or more other interconnects within an apparatus (e.g.,interconnects 32, 34, 36, and/or 38 in FIG. 1).

The interference detector 52 may include any form of device, component,or functionality that is capable of detecting the presence ofinterference, either through direct or indirect measurement ofinterference energy or through measurement of one or more wirelessperformance characteristics that are affected by the presence ofinterference energy. For example, in at least one approach, theinterference detector 52 may include an error rate detector to detect anerror rate associated with a wireless receiver (e.g., a bit error rate(BER), a packet error rate, etc.). If the error rate meets apredetermined criterion (e.g., exceeds a threshold value), it may beconcluded that interference is present. In at least one implementation,multiple different threshold values are used to detect different levelsof interference so that different degrees of interference mitigation maybe invoked. In another approach, the interference detector 52 mayinclude a ranging unit to determine a wireless communication range of acorresponding apparatus. If the range meets a predetermined criterion(e.g., is less than a threshold value), it may be concluded thatinterference is present. In still another approach, the interferencedetector 52 may include a throughput measurement unit to measure thethroughput (peak or average) of a wireless unit. If the measuredthroughput meets a predetermined criterion (e.g., is less than athreshold value), it may be concluded that interference is present. Aswill be appreciated, any of a wide variety of other techniques mayalternatively be used for determining the presence of interference.

The spectral shaping unit 54 may modify the transmissioncharacteristic(s) of the interconnect 56 in any of a wide variety ofways. In one approach, for example, the spectral shaping unit 54 simplytoggles between two (or more) different data rates based on the presenceor absence of interference. For example, if a PCI Express interconnectis being used, the spectral shaping unit 54 may operate the interconnectat the standard PCI Express data rate (i.e., 2.5 Gb/s) during normaloperation, but change to a reduced data rate (e.g., 833 Mb/s orone-third speed) when interference is detected. The spectral shapingunit 54 may then, for example, change back to the standard data rateafter a fixed or variable time interval. Similarly, the spectral shapingunit 54 may change between two or more different transmissioncharacteristic combinations (e.g., from data rate A and slew rate A todata rate B and slew rate B) based on the presence or absence ofinterference. In another possible approach, the spectral shaping unit 54may iterate through a number of different transmission characteristicvalues or value combinations to determine a value or value combinationthat either minimizes interference or reduces interference to anacceptable level.

In at least one implementation, a number of different wireless standardsare supported within a single apparatus. As is well known, differentwireless standards may have different operational frequency ranges fromone another and, therefore, may be affected differently by interferencehaving a particular frequency. In accordance with at least oneembodiment of the invention, one or more new transmission characteristicvalues are selected for an interconnect, when interference has beendetected, based on a wireless application that is presently beingimplemented. For example, when an apparatus is being operated inaccordance with IEEE 802.11 a and interference is detected, a data rateis selected that is known to cause reduced interference with IEEE802.111a and when the apparatus is being operated in accordance withIEEE 802.11b and interference is detected, a data rate is selected thatis known to cause reduced interference with IEEE 802.11b, and so on. Alookup table approach may be used to select one or more appropriatevalues based on the current application. Alternatively, the selectionmay be made algorithmically or in some other fashion. After the datarate (or other transmission characteristic) has been changed, it may bechanged back to a standard value after a fixed or variable time period.

Referring to FIG. 2, although the spectral shaping unit 54 isillustrated as being directly coupled to the interconnect 56 with whichit is operating, it should be appreciated that this functionality is notlimited to such a location. That is, the spectral shaping functionalitymay be located in any of a variety of locations within an apparatus ormay be divided amongst multiple locations. In one approach, for example,the spectral shaping functionality is part of the interconnect engine.In another approach, it is implemented within the wireless circuitry(e.g., as part of a wireless protocol, etc.). In yet another approach,the spectral shaping functionality is loaded as a software driverduring, for example, installation of a wireless network card or otherwireless module. Other locations may also be used. The interferencedetection functionality may also be implemented in any of a variety oflocations within an apparatus. The spectral shaping functionality andthe interference detection functionality may be implemented in a varietyof different ways, including software, hardware, firmware, and hybridimplementations.

FIG. 3 is a block diagram illustrating example spectral shapingequipment 60 that may be used to perform spectral shaping for aninterconnect in accordance with an embodiment of the present invention.The equipment 60 may, for example, form part of the spectral shapingunit 54 of FIG. 2. As shown, the spectral shaping equipment 60 includesa data rate adjustment unit 62 and a slew rate adjustment unit 64. Thedata rate adjustment unit 62 is operative for adjusting the data rate ofa data stream before it reaches an interconnect, in response to controlinformation. Likewise, the slew rate adjustment unit 64 is operative foradjusting the slew rate of the data stream before the stream reaches theinterconnect, in response to control information. In other embodiments,only a data rate adjustment unit or only a slew rate adjustment unit isused. Other types of adjustments may alternatively be made. The spectralshaping functionality may be part of an encoder unit for encoding a datastream for delivery to the interconnect. A corresponding decoder mayalso be used at the other end of the interconnect. Similar functionalitymay also be provided to support communication in an opposite direction.

FIG. 4 is a block diagram illustrating an example data rate adjustmentunit 66 in accordance with an embodiment of the present invention. Asshown, the data rate adjustment unit 66 includes a divide-by-three unit68 and a multiplexer 70. An input data stream is applied to both aninput of the divide-by-three unit 68 and an input of the multiplexer 70.The output of the divide-by-three unit 68 is coupled to the other inputof the multiplexer 70. During normal operation, the multiplexer 70 maybe instructed to allow the input data stream to flow through to theinterconnect. When interference has been detected, however, themultiplexer 70 may be instructed to allow the output of thedivide-by-three unit 68 to flow through to the interconnect. After afixed or variable time period, or in response to some other stimuli, themultiplexer 70 may switch back to its original state. As will beappreciated, a wide variety of alternative architectures are possiblefor the data rate adjustment unit in accordance with the presentinvention.

FIG. 5 is a flowchart illustrating an example method 80 for mitigatinginterference in a wireless apparatus in accordance with an embodiment ofthe present invention. First, a determination is made that interferencemitigation should be performed (block 82). Such a determination may bemade, for example, by directly or indirectly measuring potentialinterference energy within an apparatus or by measuring a performancecharacteristic of wireless circuitry and determining that it is notwithin a desired range. Other determination techniques are alsopossible. After a determination has been made, one or more newinterconnect transmission characteristic values are selected for theinterconnect based on a wireless application that is presently beingimplemented (block 84). For example, in one approach, a first data ratemay be selected if a first wireless standard (e.g., IEEE 802.11 a) isbeing implemented, a second data rate may be selected if a secondwireless standard (e.g., IEEE 802.11b) is being implemented, and so on.Other selection techniques are also possible. The transmissioncharacteristic(s) of the interconnect is(are) then changed to theselected value(s) for use in providing communication over theinterconnect (block 86).

FIG. 6 is a flowchart illustrating an example method 90 for mitigatinginterference in a wireless apparatus in accordance with an embodiment ofthe present invention. The method 90 utilizes an iterative approach todetermine transmission characteristics for an interconnect that willprovide an enhanced level of interference mitigation. After the method90 is initiated (block 92), an interference-related parameter ismeasured (block 94). The interference-related parameter may include, forexample, a bit-error rate (BER), a wireless communication range, aninterference signal level, or any other parameter that is related tointerference. It is next determined whether the measuredinterference-related parameter value is acceptable (block 96). Forexample, if the interference-related parameter is a BER, it may bedetermined whether the measured BER is less than a threshold value. Ifthe interference-related parameter is a wireless communication range, itmay be determined whether the measured range is above a threshold value.If the interference-related parameter is an interference signal level,it may be determined whether the measured level is below a thresholdvalue, and so on. If the measured parameter value is acceptable, themethod may be terminated (block 98). If the measured parameter value isnot acceptable, one or more interconnect transmission characteristicvalues may be modified (block 100). The method 90 then returns to block94 and the interference-related parameter is again measured. The cyclemay be repeated until the measured interference-related parameter valueis acceptable. In a similar iterative method, an interference-relatedparameter is measured for each of a finite number of interconnecttransmission characteristic values or combinations of values. A value orcombination of values is then selected that results in the best measuredinterference-related parameter value. Other similar iterativeinterference mitigation techniques are also possible.

As described above, in at least one embodiment of the invention, theinventive principles are used in connection with a PCI Expressinterconnect. In a PCI Express environment, a variety of differenttechniques may be used to adjust the data rate of an interconnect inaccordance with the invention. In one possible approach, for example, aPCI Express training sequence is used to modify a data rate of aninterconnect when interference has been detected. The training sequenceis a series of ones and zeros that are delivered between two componentsat opposite ends of a PCI Express link to establish synchronizationbetween the components. For example, a wireless module may be coupled toa host chipset through a PCI Express link. To establish synchronization,the host chipset will send a training sequence to the wireless moduleand the wireless module will send a training sequence to the hostchipset. Each training sequence includes a number of bits (i.e., thedata rate identifier) that may be used to encode the data rate that thePCI Express link supports. Currently, the PCI Express protocol uses onlyone of these bits (i.e., bit #1) to indicate a rate of 2.5 Gb/s (thestandard PCI Express data rate). In accordance with the presentinvention, the other bits may be used so that the components at eitherend of a PCI Express link may indicate to one another the operatingfrequencies that they each support. This allows a component to determinea data rate that the PCI Express link may be changed to wheninterference mitigation is desired.

FIG. 7 is a flowchart illustrating an example method 108 for negotiatinga new data rate for a PCI Express or similar type interconnect wheninterference mitigation is desired. A training sequence is firstreceived by a component from a PCI Express link (block 110). Asdescribed above, the training sequence will typically have originatedwithin a component at the other end of the link (e.g., with reference toFIG. 1, the wireless unit 16 may receive a training sequence from thehost chipset 14 via interconnect 30). After the training sequence hasbeen received, a data rate identifier is extracted from the sequence(block 112). It is then determined whether the identifier contains awireless extension (WX) data rate (currently 833 Mb/s or one-third thestandard PCI Express rate) (block 114). If the identifier does includethe WX rate, it is next determined whether the rate is supported by thecomponent (block 116). If the rate is supported, the PCI Express link isoperated at the WX rate (block 118). If the WX rate is not supported, orif the identifier does not include the WX rate, the data rate identifieris searched and compared to the rates supported by the component todetermine the highest rate common to both the identifier and thecomponent (block 120). The PCI Express link is then operated at thehighest common rate (block 122). As will be appreciated, manyalternative techniques for negotiating a new data rate on a PCI Expressinterconnect also exist.

In another possible approach for adjusting the data rate (or othertransmission characteristic(s)) of a PCI Express interconnect, the PCIExpress message protocol may be used. After synchronization has beenachieved between two components coupled to a PCI Express link, thecomponents will be able to exchange meaningful data with one another. Inaccordance with at least one embodiment of the invention, a handshakingmessage may be used to effect a change in one or more transmissioncharacteristics of the PCI Express link (e.g., data rate, slew rate,data rate and slew rate, etc.). For example, if a wireless module iscommunicating with a host chipset (or other component) through a PCIExpress link, the wireless module may deliver a message to the chipsetthat indicates that the wireless module wants to change to a differentdata rate. The chipset may then respond to the wireless module in eithera positive or negative manner. If the chipset responds positively, thedata rate of the link may be changed immediately. If the chipsetresponds negatively, the wireless module may send another request for adifferent data rate. This may continue until a data rate is agreed upon.A wide variety of other message based handshaking protocols mayalternatively be used.

In still another technique for adjusting the data rate of a PCI Expressinterconnect, a configuration bit approach is used. That is, onecomponent coupled to a PCI Express link may indicate a desire to changethe data rate of the link by forcing a bit within a register to a logichigh (or logic low) value. Another component coupled to the link maythen check its capability and respond either negatively or positivelyby, for example, changing the bit back to its original value or leavingit alone. Other configuration bit response techniques are also possible.It should be appreciated that the techniques described above fornegotiating a change of data rate and/or other transmissioncharacteristics of a PCI Express interconnect are merely examples ofsome possible techniques that may be used to implement the inventiveprinciples and that many other alternative techniques also exist.

In the foregoing detailed description, various features of the inventionare grouped together in one or more individual embodiments for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimed inventionrequires more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive aspects may lie in less thanall features of each disclosed embodiment.

Although the present invention has been described in conjunction withcertain embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention as those skilled in the art readily understand.Such modifications and variations are considered to be within thepurview and scope of the invention and the appended claims.

1. A method comprising: determining that interference mitigation shouldbe performed for wireless circuitry to reduce interference generated byan interconnect; and adjusting at least one transmission characteristicassociated with said interconnect in response to said determination toreduce said interference generated by said interconnect; whereinadjusting includes initially changing a data rate of said interconnectfrom a first rate to a second rate in response to said determination andthen changing said data rate from said second rate back to said firstrate a predetermined time period later.
 2. The method of claim 1,wherein: determining includes determining that an error rate associatedwith said wireless circuitry meets a predetermined criterion.
 3. Themethod of claim 1, wherein: determining includes determining that awireless communication range of said wireless circuitry meets apredetermined criterion.
 4. The method of claim 1, wherein: determiningincludes determining that a throughput associated with said wirelesscircuitry meets a predetermined criterion.
 5. The method of claim 1,wherein: determining includes detecting interference energy that exceedsa predetermined level.
 6. The method of claim 1, wherein: adjustingincludes adjusting a slew rate of said interconnect.
 7. The method ofclaim 1, wherein: adjusting includes selecting at least one newtransmission characteristic value for use with said interconnect basedon a wireless application presently being executed.
 8. A methodcomprising: determining that interference mitigation should be performedfor wireless circuitry to reduce interference generated by aninterconnect; and adjusting at least one transmission characteristicassociated with said interconnect in response to said determination toreduce said interference generated by said interconnect; wherein saidinterconnect is a PCI Express interconnect and adjusting includesextracting a data rate identifier from a PCI Express training sequenceand using said data rate identifier to determine a new data rate forsaid interconnect.
 9. The method of claim 8, wherein: determiningincludes determining that an error rate associated with said wirelesscircuitry meets a predetermined criterion.
 10. The method of claim 8,wherein: determining includes determining that a wireless communicationrange of said wireless circuitry meets a predetermined criterion. 11.The method of claim 8, wherein: determining includes determining that athroughput associated with said wireless circuitry meets a predeterminedcriterion.
 12. The method of claim 8, wherein: determining includesdetecting interference energy that exceeds a predetermined level. 13.The method of claim 8, wherein: adjusting includes adjusting a slew rateof said interconnect.
 14. The method of claim 8, wherein adjustingincludes: determining from said data rate identifier whether a source ofsaid PCI Express training sequence supports a wireless extension datarate; using said wireless extension data rate on said PCI Expressinterconnect when said source of said PCI Express training sequence anda recipient of said PCI Express training sequence both support saidwireless extension data rate; and identifying a highest data ratesupported by both said source and said recipient of said PCI Expresstraining sequence when said source does not support said wirelessextension data rate.
 15. A method comprising: determining thatinterference mitigation should be performed for wireless circuitry toreduce interference generated by an interconnect; and adjusting at leastone transmission characteristic associated with said interconnect inresponse to said determination to reduce said interference generated bysaid interconnect; wherein said interconnect is a PCI Expressinterconnect and adjusting includes sending a handshake messagerequesting a new data rate using a PCI Express messaging protocol. 16.The method of claim 15, wherein: determining includes determining thatan error rate associated with said wireless circuitry meets apredetermined criterion.
 17. The method of claim 15, wherein:determining includes determining that a wireless communication range ofsaid wireless circuitry meets a predetermined criterion.
 18. The methodof claim 15, wherein: determining includes determining that a throughputassociated with said wireless circuitry meets a predetermined criterion.19. The method of claim 15, wherein: determining includes detectinginterference energy that exceeds a predetermined level.
 20. The methodof claim 15, wherein: adjusting includes adjusting a slew rate of saidinterconnect.
 21. The method of claim 15, wherein: adjusting includessending another handshake message requesting a different new data rate,using a PCI Express messaging protocol, when a negative response isreceived to a previous handshake message.
 22. An apparatus comprising:means for determining whether interference mitigation should beperformed for wireless circuitry to reduce interference generated by aninterconnect; and means for adjusting at least one transmissioncharacteristic associated with said interconnect in response to adetermination to reduce said interference generated by saidinterconnect; wherein said means for adjusting initially changes a datarate of said interconnect from a first rate to a second rate in responseto said determination and then changes said data rate from said secondrate back to said first rate a predetermined time period later.
 23. Theapparatus of claim 22, wherein: said means for adjusting also adjusts aslew rate of said interconnect in response to said determination. 24.The apparatus of claim 22, wherein: said means for adjusting includesmeans for selecting at least one new transmission characteristic valuefor use with said interconnect based on a wireless application presentlybeing executed.
 25. An apparatus comprising: means for determiningwhether interference mitigation should be performed for wirelesscircuitry to reduce interference generated by an interconnect; and meansfor adjusting at least one transmission characteristic associated withsaid interconnect in response to a determination to reduce saidinterference generated by said interconnect; wherein said interconnectis a PCI Express interconnect and said means for adjusting includesmeans for extracting a data rate identifier from a PCI Express trainingsequence and means for using said data rate identifier to determine anew data rate for said interconnect.
 26. The apparatus of claim 25,wherein: said means for adjusting further includes means for adjusting aslew rate of said interconnect in response to said determination. 27.The apparatus of claim 25, wherein said means for adjusting includes:means for determining from said data rate identifier whether a source ofsaid PCI Express training sequence supports a wireless extension datarate; means for using said wireless extension data rate on said PCIExpress interconnect when said source of said PCI Express trainingsequence and a recipient of said PCI Express training sequence bothsupport said wireless extension data rate; and means for identifying ahighest data rate supported by both said source and said recipient ofsaid PCI Express training sequence when said source does not supportsaid wireless extension data rate.
 28. An apparatus comprising: meansfor determining whether interference mitigation should be performed forwireless circuitry to reduce interference generated by an interconnect;and means for adjusting at least one transmission characteristicassociated with said interconnect in response to a determination toreduce said interference generated by said interconnect; wherein saidinterconnect is a PCI Express interconnect and said means for adjustingincludes means for sending a handshake message requesting a new datarate using a PCI Express messaging protocol.
 29. The apparatus of claim28, wherein: said means for adjusting further includes means foradjusting a slew rate of said interconnect in response to saiddetermination.
 30. The apparatus of claim 28, wherein: said means foradjusting includes means for sending another handshake messagerequesting a different new data rate, using a PCI Express messagingprotocol, when a negative response is received to a previous handshakemessage.